/**
 * htmlParser改造自: https://github.com/blowsie/Pure-JavaScript-HTML5-Parser
 */

var startTag = /^<([-A-Za-z0-9_]+)((?:\s+[a-zA-Z_:][-a-zA-Z0-9_:.]*(?:\s*=\s*(?:(?:"[^"]*")|(?:'[^']*')|[^>\s]+))?)*)\s*(\/?)>/,
  endTag = /^<\/([-A-Za-z0-9_]+)[^>]*>/,
  attr = /([a-zA-Z_:][-a-zA-Z0-9_:.]*)(?:\s*=\s*(?:(?:"((?:\\.|[^"])*)")|(?:'((?:\\.|[^'])*)')|([^>\s]+)))?/g;

// Empty Elements - HTML 5
var empty = makeMap("area,base,basefont,br,col,frame,hr,img,input,link,meta,param,embed,command,keygen,source,track,wbr");

// Block Elements - HTML 5
var block = makeMap("a,address,code,article,applet,aside,audio,blockquote,button,canvas,center,dd,del,dir,div,dl,dt,fieldset,figcaption,figure,footer,form,frameset,h1,h2,h3,h4,h5,h6,header,hgroup,hr,iframe,ins,isindex,li,map,menu,noframes,noscript,object,ol,output,p,pre,section,script,table,tbody,td,tfoot,th,thead,tr,ul,video");

// Inline Elements - HTML 5
var inline = makeMap("abbr,acronym,applet,b,basefont,bdo,big,br,button,cite,del,dfn,em,font,i,iframe,img,input,ins,kbd,label,map,object,q,s,samp,script,select,small,span,strike,strong,sub,sup,textarea,tt,u,var");

// Elements that you can, intentionally, leave open
// (and which close themselves)
var closeSelf = makeMap("colgroup,dd,dt,li,options,p,td,tfoot,th,thead,tr");

// Attributes that have their values filled in disabled="disabled"
var fillAttrs = makeMap("checked,compact,declare,defer,disabled,ismap,multiple,nohref,noresize,noshade,nowrap,readonly,selected");

// Special Elements (can contain anything)
var special = makeMap("wxxxcode-style,script,style,view,scroll-view,block");

function HTMLParser(html, handler) {
  var index, chars, match, stack = [], last = html;
  stack.last = function () {
    return this[this.length - 1];
  };

  while (html) {
    chars = true;

    // Make sure we're not in a script or style element
    if (!stack.last() || !special[stack.last()]) {

      // Comment
      if (html.indexOf("<!--") == 0) {
        index = html.indexOf("-->");

        if (index >= 0) {
          if (handler.comment)
            handler.comment(html.substring(4, index));
          html = html.substring(index + 3);
          chars = false;
        }

        // end tag
      } else if (html.indexOf("</") == 0) {
        match = html.match(endTag);

        if (match) {
          html = html.substring(match[0].length);
          match[0].replace(endTag, parseEndTag);
          chars = false;
        }

        // start tag
      } else if (html.indexOf("<") == 0) {
        match = html.match(startTag);

        if (match) {
          html = html.substring(match[0].length);
          match[0].replace(startTag, parseStartTag);
          chars = false;
        }
      }

      if (chars) {
        index = html.indexOf("<");
        var text = ''
        while (index === 0) {
          text += "<";
          html = html.substring(1);
          index = html.indexOf("<");
        }
        text += index < 0 ? html : html.substring(0, index);
        html = index < 0 ? "" : html.substring(index);

        if (handler.chars)
          handler.chars(text);
      }

    } else {

      html = html.replace(new RegExp("([\\s\\S]*?)<\/" + stack.last() + "[^>]*>"), function (all, text) {
        text = text.replace(/<!--([\s\S]*?)-->|<!\[CDATA\[([\s\S]*?)]]>/g, "$1$2");
        if (handler.chars)
          handler.chars(text);

        return "";
      });


      parseEndTag("", stack.last());
    }

    if (html == last)
      throw "Parse Error: " + html;
    last = html;
  }

  // Clean up any remaining tags
  parseEndTag();

  function parseStartTag(tag, tagName, rest, unary) {
    tagName = tagName.toLowerCase();

    if (block[tagName]) {
      while (stack.last() && inline[stack.last()]) {
        parseEndTag("", stack.last());
      }
    }

    if (closeSelf[tagName] && stack.last() == tagName) {
      parseEndTag("", tagName);
    }

    unary = empty[tagName] || !!unary;

    if (!unary)
      stack.push(tagName);

    if (handler.start) {
      var attrs = [];

      rest.replace(attr, function (match, name) {
        var value = arguments[2] ? arguments[2] :
          arguments[3] ? arguments[3] :
            arguments[4] ? arguments[4] :
              fillAttrs[name] ? name : "";

        attrs.push({
          name: name,
          value: value,
          escaped: value.replace(/(^|[^\\])"/g, '$1\\\"') //"
        });
      });

      if (handler.start) {
        handler.start(tagName, attrs, unary);
      }

    }
  }

  function parseEndTag(tag, tagName) {
    // If no tag name is provided, clean shop
    if (!tagName)
      var pos = 0;

    // Find the closest opened tag of the same type
    else {
      tagName = tagName.toLowerCase();
      for (var pos = stack.length - 1; pos >= 0; pos--)
        if (stack[pos] == tagName)
          break;
    }
    if (pos >= 0) {
      // Close all the open elements, up the stack
      for (var i = stack.length - 1; i >= pos; i--)
        if (handler.end)
          handler.end(stack[i]);

      // Remove the open elements from the stack
      stack.length = pos;
    }
  }
};


function makeMap(str) {
  var obj = {}, items = str.split(",");
  for (var i = 0; i < items.length; i++)
    obj[items[i]] = true;
  return obj;
}

module.exports = HTMLParser;